Open-ended concept elicitation with breast cancer (BC) patient advocates to inform patient-reported outcome (PRO) endpoints in neoadjuvant and adjuvant trials of trastuzumab emtansine (T-DM1)

172 Background: There is no standard for measuring health-related quality of life (HRQoL) using PROs in (neo)adjuvant BC clinical trials. Further, in (neo)adjuvant treatment (tx), pre-surgical cytotoxic therapy may initially worsen HRQoL. The development of tools to measure PRO endpoints in (neo)adjuvant clinical trials could be improved with a better understanding of the issues that impact HRQoL in this population. Patient (Pt) advocates, many of whom are BC survivors, may provide valuable insight to inform PRO strategy and optimal selection of PRO endpoints in clinical trials. Methods: A workshop with BC pt advocates was conducted to inform T-DM1 BC PRO strategy. It consisted of open-ended concept elicitation to identify symptomatology, tx-related side effects, and common reasons for tx discontinuation during (neo)adjuvant therapy for BC. Results: For younger pts, hot flashes and issues with sexuality and fertility were described as the most concerning issues. For older pts, peripheral neuropathy was described as the most concerning issue. Regardless of age, most pts reportedly struggle with cognitive dysfunction, anxiety, and depression. Chemotherapy-associated side effects considered most distressing to pts of all ages were alopecia, fatigue, diarrhea, neutropenia, peripheral neuropathy, and hand-foot syndrome (HFS). Neutropenia was considered most likely to cause a physician-instigated tx break, and HFS was most likely to precipitate a pt-instigated tx break. Assessing post-operative pain and satisfaction with post-surgical tx outcome (whether breast conserving or mastectomy) were emphasized. Conclusions: Open-ended concept elicitation with pt advocates is a collaborative and informative way to identify the most relevant concepts for further study. Increased collaboration with advocates to support qualitative research may improve the ability of trial results to assist pts in making informed tx decisions. Earlier engagement of pts and advocates can support the development of new PROs that offer more precision and inform PRO instrument selection to adequately quantify tx impact.